Vegetarian Nutrition (VN) DPG Public Library

Wang Y, Liu B, Han H, et al.
Journal: Nutrition Journal
Published: 2023

Key Points

• Aim: This study explored the associations between adherence to plant-based dietary patterns and the incidence of type 2 diabetes (T2D), cardiovascular disease (CVD), cancer, and mortality among adults.

• Study design: This study is a systematic review and meta-analysis of prospective observational studies that included 76 publications reporting on 55 cohorts with a total of 2,230,443 participants.

• Inverse associations were observed between higher adherence to a plant-based dietary pattern and the risks of CVD, T2D, cancer, and all-cause mortality.

  • The inverse associations were stronger when the intervention diets emphasized healthy plant-based foods like vegetables, fruits, whole grains, and legumes.

  • Inverse associations with plant-based diets and CVD were driven mainly by CHD and not stroke.

  • Vegan or vegetarian diet patterns were associated with a slightly lower risk of CVD, T2D, and cancer compared to plant-based dietary patterns (which may have included small amounts of animal foods), however, the risk reduction was similar for mortality.

• Healthy vs Unhealthy Plant-Based

  • Unhealthy plant-based diets were positively associated with these disease outcomes.

  • Healthful plant-based dietary patterns showed stronger associations with lower risk of CVD, T2D, and cancer compared to overall plant-based patterns.

• Location: The association between plant-based dietary patterns and CVD was significantly stronger in studies conducted in Asia and Australia.

• Quality of evidence: The limitations of this meta-analysis include small sample sizes in some studies, variations in study designs and analyses, differences in clinical characteristics and populations sampled, and the majority of studies lacking repeated measurement of dietary intake.

• Proposed mechanisms for the favorable effects of plant-based diets include lower energy density, potential cholesterol-lowering effects, improved blood lipid profiles, the absence or reduction of meat, and the presence of polyphenols and other beneficial nutrients.

Conclusion

The study suggests that plant-based dietary patterns, especially those based on healthy plant food sources, may be beneficial for the primary prevention of CVD, T2D, cancer, and mortality.

Editor’s Note: This study emphasizes the importance of diet quality and the difference between healthful and unhealthful plant-based diets. The researchers emphasize that the plant-based dietary patterns performed nearly as well as the vegan and vegetarian patterns, supporting a more flexible approach—it is easier for many people to include more healthy plant foods in their diet as opposed to eliminating all animal foods. It's important to note that these findings are based on observational studies, and further research, including randomized controlled trials, is needed to establish causation and explore the underlying mechanisms in more detail. In addition, future research is warranted to investigate the other variables responsible for the significantly greater risk reductions found in plant-based diet studies conducted in Asia and Australia.